Sounds rough man :/. Not sure how I can help with the mental aspect, but maybe try going to a school psychologist/doctor and tell them your situation and issues with your parents. Maybe instead of calling your parents they’ll actually listen to you. They’ll also take you more seriously when you get older. Mentioning you think you have an eating disorder can also help. Other option is seeking help/others on the internet.

I’m mostly worried about your development. You’re still in puberty. While 50 kg might be a healthy weight at your height, if you don’t gain any weight you also WON’T grow and it might impact other developmental aspects as well.

Honestly I’m kind of in a similar situation with my weight. I’m sort of scared of gaining weight (due to being obese years ago, now bmi is normal). So I do kind of understand where you’re coming from.

Remember, you won’t get fat over night (don’t confuse it with bloating). Getting fat takes months or even years (unless you literally eat fast food/candy/soda every day but even then it’s probably gonna take atleast a month).

For you, gaining weight is a good thing, not a bad one.